GDM3: Black screen with blinking cursor

[Luis Alberto Pabón]

About a month ago, GDM ceased to work. I opened another issue here https://bugs.launchpad.net/ubuntu/+source/gdm3/+bug/1908717 but due to me using oibaf's ppa it was considered prudent to discard that issue and re-open after I removed the ppa and restored Ubuntu's dist packages.

Upon boot, gdm goes to a black screen with a cursor. This screen flickers to show the underlying tty and on each flicker the cursor position resets to the bottom right. It will do this a number of times until GDM dies and I'm left on a tty.

I can start my window manager (sway) without issue from the console still and everything functions normally.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: gdm3 3.36.3-0ubuntu0.20.04.2
ProcVersionSignature: Ubuntu 5.4.0-53.59-generic 5.4.65
Uname: Linux 5.4.0-53-generic x86_64
ApportVersion: 2.20.11-0ubuntu27.14
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: sway
Date: Thu Jan 7 15:55:43 2021
SourcePackage: gdm3
UpgradeStatus: No upgrade log present (probably fresh install)

[Luis Alberto Pabón (copong)]

I have temporarily switched to lightdm, which works fine.

Recording of the issue:

https://www.youtube.com/watch?v=6VaizT4uC8w&feature=youtu.be

[Daniel van Vugt (vanvugt)]

Thanks for the bug report.

Please run:

  lspci -kv > lspci.txt
  journalctl -b0 > journal.txt
  journalctl -b-1 > prevjournal.txt

and attach the resulting files here.

[Daniel van Vugt (vanvugt)]

Thanks. prevjournal.txt does seem to show gnome-shell repeatedly failing with:

Jan 07 16:03:33 luis-XPS-15-9560 gnome-shell[2211]: JS ERROR: Error: Requiring NMA, version none: Typelib file for namespace 'NMA' (any version) not found
                                                    @resource:///org/gnome/shell/misc/modemManager.js:4:35
                                                    @resource:///org/gnome/shell/ui/status/network.js:12:22
                                                    _init@resource:///org/gnome/shell/ui/panel.js:726:13
                                                    _ensureIndicator@resource:///org/gnome/shell/ui/panel.js:1069:25
                                                    _updateBox@resource:///org/gnome/shell/ui/panel.js:1080:34
                                                    _updatePanel@resource:///org/gnome/shell/ui/panel.js:1026:14
                                                    _init@resource:///org/gnome/shell/ui/panel.js:835:14
                                                    _initializeUI@resource:///org/gnome/shell/ui/main.js:206:13
                                                    start@resource:///org/gnome/shell/ui/main.js:146:5
                                                    @<main>:1:47
Jan 07 16:03:33 luis-XPS-15-9560 gnome-shell[2211]: Execution of main.js threw exception: Script <main> threw an exception
Jan 07 16:03:33 luis-XPS-15-9560 gnome-shell[2211]: Attempting to call back into JSAPI during the sweeping phase of GC. This is most likely caused by not destroying a Clutter actor or Gtk+ widget with ::destroy signals connected, but can also be caused by using the destroy(), dispose(), or remove() vfuncs. Because it would crash the application, it has been blocked and the JS callback not invoked.
Jan 07 16:03:33 luis-XPS-15-9560 org.gnome.Shell.desktop[2211]: == Stack trace for context 0x5617ef98b780 ==
Jan 07 16:03:33 luis-XPS-15-9560 gnome-shell[2211]: The offending signal was destroy on Gjs_ui_panel_AggregateMenu 0x5617efc96c60.

-----------------------

Jan 07 16:03:37 luis-XPS-15-9560 gnome-shell[2645]: JS ERROR: Error: Requiring NMA, version none: Typelib file for namespace 'NMA' (any version) not found
                                                    @resource:///org/gnome/shell/misc/modemManager.js:4:35
                                                    @resource:///org/gnome/shell/ui/status/network.js:12:22
                                                    _init@resource:///org/gnome/shell/ui/panel.js:726:13
                                                    _ensureIndicator@resource:///org/gnome/shell/ui/panel.js:1069:25
                                                    _updateBox@resource:///org/gnome/shell/ui/panel.js:1080:34
                                                    _updatePanel@resource:///org/gnome/shell/ui/panel.js:1026:14
                                                    _init@resource:///org/gnome/shell/ui/panel.js:835:14
                                                    _initializeUI@resource:///org/gnome/shell/ui/main.js:206:13
                                                    start@resource:///org/gnome/shell/ui/main.js...

[Daniel van Vugt (vanvugt)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. It sounds like some part of the system has crashed. To help us find the cause of the crash please follow these steps:

1. Look in /var/crash for crash files and if found run:
    ubuntu-bug YOURFILE.crash
Then tell us the ID of the newly-created bug.

2. If step 1 failed then look at https://errors.ubuntu.com/user/ID where ID is the content of file /var/lib/whoopsie/whoopsie-id on the machine. Do you find any links to recent problems on that page? If so then please send the links to us.

3. If step 2 also failed then apply the workaround from bug 994921, reboot, reproduce the crash, and retry step 1.

Please take care to avoid attaching .crash files to bugs as we are unable to process them as file attachments. It would also be a security risk for yourself.

[Luis Alberto Pabón (copong)]

Thank you Daniel. None of the 3 ways to get ahold of a crash report worked unfortunately. There's nothing on /var/crash even after applying the workaround (Adding 'Crash' to the problem_types list on crashdb) and https://errors.ubuntu.com/user/5955c0a85343a54d5d779518dadcd4e278745d94628b423987bea5979d44b1d2b9ed23756ac91f32035088000d8d2ae868a6c9b99b7aff70d4febf3d6df571d2 as you can see is empty.

[Luis Alberto Pabón (copong)]

The error you posted got me thinking and I did a reinstall of libnma0 and gir1.2-nm-1.0 and now the problem went away. Somehow, something on these got foobared. I never had any networkmanager issues though.

[Daniel van Vugt (vanvugt)]

OK, thanks. If the problem returns then we can reopen the bug.

[Luis Alberto Pabón (copong)]

Roger that, thank you.